1. Field of the Invention
The present invention relates to a thermoelectric conversion device using Peltier effect or Seebeck effect of a semiconductor, and more specifically, to a sealing structure for preventing water from entering from the exterior to the interior of the device, and an improved structure of electric connection between the interior and the exterior of the device.
2. Description of the Related Art
In general, the thermoelectric conversion device of this type is, as shown in Japanese Patent Laid-Open No. 207762/1994 for example, a sandwich construction in which a thermoelectric conversion circuit including a plurality of P-type semiconductor devices and N-type semiconductor device arranged in two-dimensional matrix and connected electrically in series is sandwiched between two plates, and two leads extending from the thermoelectric conversion circuit are drawn out of the plates for connection with the external power supply. When a direct current is passed through the thermoelectric conversion device, it serves as a heat pump in which the plate on one side absorbs heat and the plate on the other side discharges heat, or in contrast to it, heating the plate on one side and cooling the plate on the other side generates a direct current.
Such thermoelectric conversion device often used is in the field of the cooling apparatus. Therefore, the gap (typically the gap between the outer edge portions of two plates) around the outer periphery of the device must be sealed in order to prevent water generated outside of the device due to dew condensation or the like from entering the thermoelectric conversion circuit in the device.
From this point of view, the thermoelectric conversion device disclosed in Japanese Patent Laid-Open No. 207762/1994 is provided with an O-ring interposed in the gap between the outer edge portions of two plates all over the periphery, and the two plates are tightened with a bolt so that they come in close contact with the O-ring. In addition, an adhesive is circumferentially filled in the groove formed between two plates on the outer periphery of the O-ring. Such a double sealing structure using the O-ring and an adhesive ensures sealing the gap between the outer edge portions of those two plates. In addition, a through hole is formed through one of the plate, through which the lead extending form the thermoelectric conversion circuit passes. The gap between the through hole and the lead is sealed with an adhesive filled therein.
In the thermoelectric conversion device disclosed in Japanese Patent Laid-Open No. 207762/1994, disadvantageously, a close attention must be paid to the steps for manufacturing the seal in the gap between the through hole and the lead, and thus it needs lots of time and troublesome process management. In other words, the process comprises the steps of passing the lead through the through hole, filling an adhesive in the gap between the through hole and the lead, and curing the adhesive. It is required to stand the device still so as not to touch or vibrate the lead during the time period from the time when the adhesive is filled until it is completely cured. Otherwise, the lead moves in the through hole, which generates a gap between the adhesive and the lead or the like, and thus the perfect seal cannot be made. Therefore, the sealing structure of the thermoelectric conversion device in the related art is not actually suitable for effective manufacture in the factory.
Accordingly, it is an object of the present invention to provide a sealing structure of the thermoelectric conversion device that has high sealing capability and can be manufactured in a simple manner.
The thermoelectric conversion device according to the present invention constructed of a thermoelectric conversion circuit interposed between two plates comprises: an outer edge sealing member for enclosing the outer periphery of the thermoelectric conversion circuit to seal the gap between the outer edge portions of two plates, a through hole formed on at least one of the two plates from the inner surface through the outer surface, a connector passed through the through hole and connected at one end to the thermoelectric conversion circuit for connecting the thermoelectric conversion circuit to the external power supply, and a connector sealing member that is constructed to seal the gap between the connector and the through hole spontaneously when the connector is inserted through the through hole and fixed at the prescribed position.
The thermoelectric conversion device comprises a connector for connecting the thermoelectric conversion circuit in the device to the external power supply, and the connector is inserted through the through hole that passes through the plates sandwiching the thermoelectric conversion circuit. The connector sealing member for sealing the gap between the connector and the through hole is constructed to seal the gap between the connector and the through hole spontaneously in the course of inserting the connector through the through hole and fixing the same at the prescribed position. Therefore, since the seal between the connector and the through hole is completed spontaneously by the step of inserting the connector into the through hole and fixing the same at the prescribed position in a method of manufacturing the device, it can be manufactured easily and exhibits high sealing capability.
For example, an O-ring that is fitted on the connector may be used as a connector-sealing member. The O-ring is brought into close contact with the surface of the connector and the inner peripheral surface of the through hole, or is brought into close contact with the surface of the connector and the surface of the plate around the through hole, and seals the gap formed there between spontaneously in the course of inserting it through the through hole and fixing the same at the prescribed position. In this way, the sealing operation is easy, and preferable sealing effect can be realized since the sealing capability of the O-ring itself is significantly high.
In one preferable embodiment, the outer diameter of the portion inserted into the through hole of the connector is almost the same as the inner diameter of the through hole. Therefore, the connector does not unnecessarily rattle in the through hole when it is inserted into the through hole, which contributes to the simplification of the operation and improvement of the sealing capability. When the outer diameter of the portion inserted through the through hole of the connector is almost the same as the inner diameter of the through hole, a sealing tape can be used as a connector-sealing member instead of the O-ring. In other words, the seal is completed simply by the steps of winding a suitable amount of the sealing tape on the outer periphery of the portion to be inserted into the through hole of the connector, and inserting the same through the through hole. The portion to be inserted through the through hole of the connector and the through hole may be engaged by the male screw and the female screw.
One preferable embodiment comprises a through hole formed on the plate described above from the inner surface through the outer side surface, and the connecter inserted therein extends out from the side surface of the thermoelectric conversion device.
The thermoelectric conversion device according to the present invention can be manufactured by the method comprising the steps of; sandwiching the thermoelectric conversion circuit between two plates; enclosing the outer periphery of the thermoelectric conversion circuit to seal the gap between the outer edge portions of two plates by means of outer edge sealing member, forming a through hole on at least one of the two plates from the inner surface through the outer surface, inserting the connector for connecting the thermoelectric conversion circuit to the outer power supply though the through hole and fixing the prescribed position, connecting one end of the connector to the thermoelectric conversion circuit, and using the connector-sealing member so as to seal the gap between the connector and the through hole spontaneously when the connector is inserted through the through hole and fixed at the prescribed position. These steps do not have to be performed in the order shown above, and they may be performed in the different order according to the specific construction of the thermoelectric conversion device and convenience in manufacturing.